Motor Terminal Temperature Ratings

4 replies [Last post]
rbarnett's picture
Joined: 2014-03-04

I always hear motor terminals are rated for 75 degrees C. I guess that must be true. But where in the Code does it say that?

dpiper's picture
Joined: 2014-05-28

NEC 110.15(C)(4) states, "For motors marked with design letters B, C, or D, conductors having an insulation rating of 75°C (167°F) or higher shall be permitted to be used, provided the ampacity of such conductors does not exceed the 75°C (167°F) ampacity.

dcarroll's picture
Joined: 2014-02-04

NEC 2014. The specific Section is 110.14(C)(1)(a)(4).

skd76's picture
Joined: 2013-09-11

The 2013 UL Whitebook motor category PRGY Product Markings section calls out this info. Either 60c, 60c/75c, or 75c only conductors are the range shown as having been investigated with motors by their test lab. 110.3(B) is an applicable Code section for this type of NRTL limitation. An Electrical Code book isn't always where we need to look.

sparky377's picture
Joined: 2013-10-07


I assume your reference is from the 2014 NEC. In the 2011 NEC it is actually 110.14(C)(1)(a)(4). Would the ...(1)(a)... also be the case in the 2014 edition?

BTW: I reference the 2011 NEC because both of the major authorities in my area are on the '08 and '11 editions, respectively, and are not expecting to update until March or May of 2015. Has to do with coordinating updates with the building codes and authorizing legislation for many dozens of municipalities that contract with the county for inspections.

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